The present invention relates to a graphics processing device and, more particularly, to a graphics processing device, such as a computer-aided design (CAD) device or the like, having an additional function of recognizing and extracting a characteristic point of an image to be referenced for the graphic operation to be carried out by a graphic operation processing function.
Heretofore, pictures drawn on paper have been inputted into a graphics processing system as image data by means of an image scanner or the like. The image data are then displayed on a display screen through the graphics processing system and the operator has manually inputted through a pointing device or the like by tracing the image data on the screen.
For example, Japanese Patent Unexamined Publication (Kokai) No. 62-269,276/1987 discloses an interactive graphics input system in which a picture is scanned by an image scanner and inputted into a computer as image data, which in turn are displayed on a display screen while superposing center line image data on the image data. The graphics are input as vector data by designating the positions required for the graphics on the display screen by means of a coordinate designator.
In converting the image data into the graphics data (coordinate points data) such as vector data, for example, in the manner as described hereinabove, the center data for the center or center line of the image are first given, and then necessary data such as an end point, branch point or corner point as the characteristic point of the image are selected from the center data, and such necessary data are inputted. In this case, in the conventional technique, the characteristic points have been inputted while the center data are superposed on the image data on the display screen. Hence, the display screen is forced to become so complicated that the operator has failed to select necessary data in an efficient way.
For instance, in the conventional technique, when the image data are converted into vector data as the graphic data for the characteristic point of a transversely lying, inverted L-shaped linear graphic form as shown in FIG. 5, the center point data 51 are first given from the image data 50 and, while both the center point data 51 and the image data 50 are displayed on the screen, the corner point 52 is selected from the center point data as the characteristic point and the graphic data are inputted by designating the corner point 52 as the characteristic point of the image.
As described hereinabove, however, the conventional graphics operation method in which the graphics data (vector data) are inputted requires the picture to be inputted as the image data to thereby give the center point data, followed by manually selecting the corner point 52 on the display screen in order to designate the characteristic point. Hence, the operation should be carried out twice in order to obtain the graphics data so that this operation for obtaining the graphics data is quite complicated. Further, the inputting is implemented manually so that the characteristic points may not ways be designated in an accurate fashion, and thus the graphics data inputted may cause an error.